1. Field of the Invention
The present invention relates to a high temperature, high efficiency lamp apparatus with an improved configuration that produces a beam of light using a bulb containing a fill that is energized to vaporize the fill. More particularly, the present invention relates to a projecting system that features a lamp in which light energy is generated by a plasma contained inside a cylindrical ceramic sleeve that has a surface with reflecting properties.
2. Description of the Related Art
High power lamps are used for illumination applications beyond typical incandescent and fluorescent lamps. One type of lamp known as a high intensity discharge (HID) lamp consists of a glass envelope and a fill which vaporizes and becomes a gas when the lamp is operated. U.S. Pat. No. 5,404,076, issued to Dolan, et al. and entitled "Lamp Including Sulfur," discloses an electrodeless lamp with a fill of sulfur, selenium, or compounds of these substances. The fill is excited through electromagnetic energy supplied from external electrodes. The Dolan, et al. U.S. Pat. No. 5,404,076 is incorporated herein by reference.
Projecting systems are used to display images on large surfaces, such as computer displays or television screens. For example, in a front projection system, an image beam is projected from an image source onto the front side of a reflection-type angle transforming screen, which then reflects the light toward a viewer positioned in front of the screen. In a rear projection system, the image beam is projected onto the rear side of a transmission-type angle transforming screen and transmitted toward a viewer located in front of the screen.
Prior co-pending U.S. patent application Ser. No. 08/581,108, entitled "Projecting Images," to Knox, filed Dec. 29, 1995, discloses a method of displaying an optical image by projecting the image along an optical path and at an optical device interposed across the optical path, at one time reflecting the image from the optical device and at a different time permitting the image to pass through the optical device to be displayed. U.S. application Ser. No. 08/581,108, entitled "Projecting Images," to Knox, filed Dec. 29, 1995, is incorporated herein by reference.
The image source for such projection systems employs a light that must be of high intensity and preferably produced very efficiently. Further, the light is preferably provided from a very small aperture, as close to being a "point source" as possible. If an optical image is to being displayed by projection, it sometimes passes through an optical device interposed across the optical path. In the projection system of prior co-pending U.S. application Ser. No. 08/581,108, filed Dec. 29, 1995, one or more optical devices reflect the image at one time from the optical device and at a different time permit the image to pass through the optical device to be displayed. There will be a decrease in light intensity once the optical image strikes the optical device interposed across the optical path. Therefore, in projection systems where an optical device is interposed across the optical path there is a need for a projection engine with a high intensity light of improved efficiency. U.S. patent application Ser. No. 08/747,190, entitled "High Efficiency Lamp Apparatus for Producing a Beam of Polarized Light," to Knox, et al., filed Nov. 12, 1996, discloses a high efficiency lamp apparatus for producing polarized light. The apparatus redirects reflected light of one polarity back to the light source. U.S. application Ser. No. 08/747,190 is hereby incorporated by reference.